Background & Objectives: Endothelium nitric oxide synthase (eNOS) is a type of enzyme which produces an endogenous factor called nitric oxide (NO). NO plays important role in progress of euplastic diseases. In chronic gastritis, the increased level of NO causes damages to DNA. The aim of present study is to evaluate eNOS concentration in sera of healthy people and those infected by Helicobacter pylori .

  Methods: The sera and stool specimens from 84 voluntaries (Female: 58.3%, Males 41.6%) were collected. Helicobacter pylori antigen in the stool specimens and eNOS levels in sera were determined using ELISA . Obtained data were analyzed using Excell software.

  Results : The age range was from 1 to 78 years old (Mean: 30 years old). In terms of special diseases, 70.2% did not have any special diseases, but 29.76% showed at least one special disease, mainly thyroid disease and hypertension. The results for H. pylori stool antigen detection showed that 16.6%, 29.76% and 53.57% of collected specimens were equivocal, Helicobacter pylori negative and positive respectively. Comparison of sera concentrations of eNOS showed that there is no significant change among these three groups.

  Conclusion : As mentioned in results, the eNOS sera concentrations showed no significant change in Helicobacter pylori positive and negative groups. Albeit the other studies showed the significant increase in serum concentration of Helicobacter pylori positive patient, this controversy may arise from race and variations in Helicobacter pylori pathogenic islands such as those containing VacA and CagA. We propose to conduct a similar study in Ardabil to focus on the pathogenic islands of H. pylori strains in this province.